Japanese Laid-Open Patent Publication No. 2002-163792 (Patent Literature 1) discloses a system in which an image of a curved section of a road is captured with a camera installed on the road side to detect an obstacle, and the result of the obstacle detection is provided to a driver of a vehicle by using a road-to-vehicle communication device.
Meanwhile, Japanese Laid-Open Patent Publication No. 2015-121959 (Patent Literature 2) discloses an obstacle detection device configured to detect an obstacle by using an ultrasonic sensor mounted on a vehicle, and provides the result of the obstacle detection to a driver of the vehicle.